54 



DEPARTMENT OF FISH AND GAME 



unloading and departure times for succeeding trips, 

 thus effecting a reduction in the total number of trips 

 and the total tonnage. 



Solutions to the industry's problems were sought on 

 all fronts, from intensified advertising campaigns to 

 seeking governmental aid via direct subsidy and/or 

 tariffs. Efforts were not without some reward, particu- 

 larly in the increase of consumption. 



The ultimate objective of the department's tuna in- 

 \estigation is the same as for other fisheries under 

 study by the iMarine Fisheries Branch. That is to ob- 

 tain necessary information on which to base recom- 

 mendations for such management of marine life as is 

 necessary to allow a continued harvest at the highest 

 possible level. This requires determinations of the size 

 of the stocks, fluctuations in abundance, levels of ex- 

 ploitation, etc. Tuna research activities during the 

 biennium were directed toward the solution of these 

 problems. 



Tagging Program 



The full scale tagging program, initiated during 

 the preceding biennium, was actively carried forward 

 during this one. Eleven tagging teams sailing on as 

 many commercial fishing vessels, liberated over 6,200 

 tuna with the department's originally designed tags 

 of \\ hire vinyl plastic tubing. 



Tuna fishing from the stem of o modern iuna clipper in the eastern 



fropicat Pacific Ocean. Eleven teams from the department tagged tuna 



aboard such vessels during the biennium. 



(Fish and Game Photo) 



Accumulated tag return data are beginning to un- 

 fold the patterns of movements of yellowfin tuna and 

 albacore. The trans-Pacific migration of albacore was 

 further substantiated by additional recoveries in Japan. 

 Yellowfin were shown to move from southern Mexico 

 northward to central Baja California, gross move- 

 ments of almost a thousand miles. These movements 

 hint at a link between the fish off the so-called "local" 

 grounds, Baja California, with those occurring off 

 Central America. Skipjack returns to date indicate 

 that additional developmental work is needed before 

 returns can be expected w hich will vield the necessary 

 data for management recommendations. 



The fish market sampling program, a long term 

 project, undertaken by the department, is designed to 

 yield a maximum amount of information regarding 

 the populations of the various tunas. By interviewing 

 the fishermen, details of the catch in time and area 

 are obtained. By measuring the lengths of the fish in 

 the catch, information is obtained on their age, rate of 

 grow th and variation in abundance. For the yellowfin- 

 skipjack fishery the gathering of this data was done 

 on a cooperative basis with the Inter-American Tropi- 

 cal Tuna Commission, effecting a saving in manpower 

 for both organizations. Substantial progress was made 

 in compiling the length frequencies for analysis which 

 was started late in the biennium. 



Log Books Help 



The use of log books is an invaluable tool in the 

 stud\- of fishery population dynamics. During the 

 biennium a chart type log book was designed for the 

 albacore fisher\'. The promising results obtained from 

 the pilot trial late in the 1954 season encouraged the 

 planning and initiation of a full scale program in 1955. 

 The first season's returns, 1955, produced a response 

 of 55 percent of the fishermen. The data obtained 

 yielded one of the most complete pictures of the 

 albacore fishery off California shores ever compiled. 



Field work at sea on survey vessels or from com- 

 mercial fishing boats yields types of information not 

 readil\' obtainable by other means. The occurrence of 

 tuna in time, distance and depth, in areas and seasons 

 not normally covered by the fishery is a case in point; 

 measurements of the environment is another. Because 

 costs are high, each cruise is designed to answer as 

 many questions and problems as is practical. The de- 

 partment's survey vessel, A^. B. Scofield, made three 

 exploratory fishing cruises for tuna during the bien- 

 nium. A fourth cruise was made by department per- 

 sonnel on the University of California's research ves- 

 sel, the Paolhia T. 



Albacore 



The albacore is the onl\' tuna that is taken in num- 

 bers north of California. The three states, Canada, and 

 the U. S. Fish and Wildlife Service have all studied 

 this species. There is vital need for these studies to 



